US20150318900A1 - Wireless power transfer system, power receiver, and wireless power transfer method - Google Patents

Wireless power transfer system, power receiver, and wireless power transfer method Download PDF

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US20150318900A1
US20150318900A1 US14/800,241 US201514800241A US2015318900A1 US 20150318900 A1 US20150318900 A1 US 20150318900A1 US 201514800241 A US201514800241 A US 201514800241A US 2015318900 A1 US2015318900 A1 US 2015318900A1
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Prior art keywords
power
resonance
coil
power source
power receiver
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English (en)
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Satoshi Shimokawa
Akiyoshi Uchida
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Fujitsu Ltd
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Fujitsu Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
    • H04B5/70—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes
    • H04B5/79—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes for data transfer in combination with power transfer
    • H04B5/0037—
    • H02J5/005—
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/05—Circuit arrangements or systems for wireless supply or distribution of electric power using capacitive coupling
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/40—Circuit arrangements or systems for wireless supply or distribution of electric power using two or more transmitting or receiving devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/80—Circuit arrangements or systems for wireless supply or distribution of electric power involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/90—Circuit arrangements or systems for wireless supply or distribution of electric power involving detection or optimisation of position, e.g. alignment
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/00032—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries characterised by data exchange
    • H02J7/00034—Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
    • H04B5/20—Near-field transmission systems, e.g. inductive or capacitive transmission systems characterised by the transmission technique; characterised by the transmission medium
    • H04B5/24—Inductive coupling
    • H04B5/26—Inductive coupling using coils
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
    • H04B5/70—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes
    • H04B5/72—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes for local intradevice communication
    • H02J7/025—

Definitions

  • Embodiments discussed herein relate to a wireless power transfer system, a power receiver and a wireless power transfer method.
  • wireless power transfer techniques for power supply and electrification have attracted attention.
  • Research and development have been conducted on wireless power transfer systems wirelessly transferring power to, e.g., various electronic devices such as mobile terminals and notebook computers, electrical household appliances or power infrastructure equipment.
  • the resonance frequency in the wireless power transfer system is, e.g., from hundreds of KHz to tens of MHz.
  • dedicated communication circuits are provided to the power source and the power receiver, respectively. Accordingly, hardware volume on each of the power source and the power receiver increases. Thus, cost increases.
  • Patent Document 1 International Publication Pamphlet No. WO2011/099071
  • Patent Document 2 Japanese Laid-open Patent Publication No. 2010-148174
  • a power receiver including a resonance coil, an oscillation unit, a communication unit, and a control unit.
  • the resonance coil is configured to wirelessly receive power from a power source using magnetic field resonance or electric field resonance
  • the oscillation unit is configured to output a voltage which oscillates at a predetermined frequency.
  • the communication unit is configured to communicate with the power source, and the control unit is configured to receive an output from the communication unit, and adjust a resonance frequency of the resonance coil using an output voltage from the oscillation unit.
  • FIG. 1 is a diagram schematically depicting a wireless power transfer system
  • FIG. 2 is a block diagram depicting one example of a wireless power transfer system
  • FIG. 3 is a block diagram depicting the wireless power transfer system depicted in FIG. 2 while focusing on a control system;
  • FIG. 4A is a diagram ( 1 ) for illustrating resonance frequency control in the wireless power transfer system depicted in FIG. 2 and FIG. 3 ;
  • FIG. 4B is a diagram ( 2 ) for illustrating resonance frequency control in the wireless power transfer system depicted in FIG. 2 and FIG. 3 ;
  • FIG. 5A is a diagram ( 1 ) for illustrating conditions for simulation in the wireless power transfer system depicted in FIG. 2 and FIG. 3 ;
  • FIG. 5B is a diagram ( 2 ) for illustrating conditions for simulation in the wireless power transfer system depicted in FIG. 2 and FIG. 3 ;
  • FIG. 6A is a diagram ( 1 ) depicting a result of simulation in the wireless power transfer system depicted in FIG. 2 and FIG. 3 , which is performed under the conditions for simulation illustrated in FIG. 5A and FIG. 5B ;
  • FIG. 6B is a diagram ( 2 ) depicting a result of simulation in the wireless power transfer system depicted in FIG. 2 and FIG. 3 , which is performed under the conditions for simulation illustrated in FIG. 5A and FIG. 5B ;
  • FIG. 7 is a block diagram depicting a wireless power transfer system according to a first embodiment
  • FIG. 8 is a block diagram depicting a wireless power transfer system according to a second embodiment
  • FIG. 9 is a diagram ( 1 ) for illustrating an operation of the wireless power transfer system depicted in FIG. 8 ;
  • FIG. 10 is a diagram ( 2 ) for illustrating an operation of the wireless power transfer system depicted in FIG. 8 ;
  • FIG. 11 is a diagram ( 3 ) for illustrating an operation of the wireless power transfer system depicted in FIG. 8 ;
  • FIG. 12 is a diagram ( 4 ) for illustrating an operation of the wireless power transfer system depicted in FIG. 8 ;
  • FIG. 13 is a block diagram depicting a wireless power transfer system according to a third embodiment
  • FIG. 14 is a diagram ( 1 ) for illustrating an operation of the wireless power transfer system depicted in FIG. 13 ;
  • FIG. 15 is a diagram ( 2 ) for illustrating an operation of the wireless power transfer system depicted in FIG. 13 .
  • FIG. 1 is a diagram schematically depicting a wireless power transfer system. As depicted in FIG. 1 , the wireless power transfer system has a primary side (power source side: a power source) 1 and a secondary side (power receiver side: a power receiver) 2 .
  • the power source 1 and the power receiver 2 may be plural.
  • the power source 1 includes an AC power supply 11 , and a Power source system coil SC including a power supply coil 12 and a power source resonance coil 13 .
  • the power receiver 2 includes a Power receiver system coil JC including a power receiver resonance coil 22 and a power extraction coil 23 , and a load device 21 .
  • the power source 1 and the power receiver 2 transfer energy (electric-power) from the power source 1 to the power receiver 2 by magnetic field resonance (magnetic field resonating) between the power source resonance coil (LC resonator) 13 and the power receiver resonance coil (LC resonator) 22 .
  • the transfer of power from the LC resonator 13 to the LC resonator 22 may be performed using electric field resonance (electric field resonating) or the like.
  • electric field resonance electric field resonating
  • the power transfer from the power supply coil 12 to the power source resonance coil 13 is performed using electromagnetic induction.
  • the power transfer from the power receiver resonance coil 22 to the power extraction coil 23 is also performed using electromagnetic induction.
  • FIG. 2 is a block diagram depicting an example of the wireless power transfer system and illustrates in more detail the wire power transfer system depicted in FIG. 1 .
  • the power transfer system includes the Power source system coil SC, the Power receiver system coil JC, the AC power supply 11 , a power source side control circuit 14 , the device 21 serving as a load, and a power receiver side control circuit 24 .
  • the Power source system coil SC includes the power supply coil 12 and the power source resonance coil 13 .
  • the power supply coil 12 is windings obtained by circumferentially winding a metal wire, e.g., a copper wire or an aluminum wire a plurality of times.
  • An AC voltage (high-frequency voltage) generated by the AC power supply 11 is applied to both ends thereof.
  • the power source resonance coil 13 includes a coil 131 obtained by circumferentially winding a metal wire, e.g., a copper wire or an aluminum wire, and a capacitor 132 connected to both ends of the coil 131 so as to form a resonance circuit configured by this coil and this capacitor.
  • a resonance frequency f 0 is expressed by the following expression.
  • L is the inductance of the coil 131
  • C is the capacitance of the capacitor 132 .
  • the coil 131 of the power source resonance coil 13 is, e.g., a one-turn coil.
  • Various types of capacitors may be used as the capacitor 132 . However, a capacitor with a minimized loss and a sufficient pressure resistance is preferable.
  • a variable capacitor is used as the capacitor 132 .
  • a variable capacity device manufactured using MEMS technology, and a variable capacity device (varactor) using a semiconductor may be applied to the variable capacitor.
  • the power supply coil 12 and the power source resonance coil 13 are arranged to be coupled electromagnetically and closely to each other.
  • these coils are concentrically arranged on a same plane.
  • these coils are arranged in a state in which the power supply coil 12 is provided inside the power source resonance coil 13 .
  • the power source resonance coil 13 and the power supply coil 12 may be coaxially arranged with an appropriate distance from each other.
  • the Power receiver system coil JC includes the power receiver resonance coil 22 and the power extraction coil 23 .
  • the power receiver resonance coil 22 includes a coil 221 formed by winding a metal wire such as a copper wire or an aluminum wire circumferentially, and a capacitor 222 connected to both ends of the coil 221 .
  • the resonance frequency f 0 of the power receiver resonance coil 22 is expressed by the above expression (1) according to the inductance of the coil 221 and the capacity of the capacitor 222 .
  • the coil 221 of the power receiver resonance coil 22 is, e.g., a one-turn coil.
  • Various types of capacitors may be applied to the capacitor 222 , as described above.
  • a variable capacitor is used as the capacitor 222 in this wireless power transfer system depicted in FIG. 2 .
  • variable capacity device manufactured using, e.g., MEMS technology, or a varactor may be applied to the variable capacitor.
  • the power extraction coil 23 is a winding obtained by circumferentially winding a metal wire, e.g., a copper wire or an aluminum wire a plurality of times.
  • the device 21 serving as a load is connected to both ends of the coil 23 .
  • the load device 21 is, e.g., a battery used as a power supply for the power receiver 2 or a circuit for charging the battery.
  • the power receiver resonance coil 22 and the power extraction coil 23 are arranged to be coupled electromagnetically and closely to each other.
  • these coils are concentrically arranged on a same plane.
  • these coils are arranged in a state in which the power extraction coil 23 is provided inside the power receiver resonance coil 22 .
  • the power receiver resonance coil 22 and the power extraction coil 23 may be coaxially arranged with an appropriate distance from each other.
  • Electric power is wirelessly transferred by the magnetic field resonance from the Power source system coil SC to the Power receiver system coil JC.
  • the Power source system coil SC and the Power receiver system coil JC are arranged within a range of an appropriate distance from each other such that the coil planes of these coils are parallel to each other and that the coil axis centers of these coils coincide with each other or are not largely shifted from each other.
  • a direction along the coil axis center KS is a main radiation direction of a magnetic field KK
  • a direction from the Power source system coil SC to the Power receiver system coil JC is a power transmitting direction SH.
  • resonance frequency control is performed by the power source side control circuit 14 and the power receiver side control circuit 24 , using the phase ⁇ vs of the AC power supply 11 and the phases ⁇ is and ⁇ ij of currents respectively flowing in the power source resonance coil 13 and the power receiver resonance coil 22 .
  • the power source side control circuit 14 detects the phase ⁇ vs of the voltage V s applied to the Power source system coil SC and the phase ⁇ is of the current Is flowing in the Power source system coil SC, and performs variable control of the resonance frequency f s of the Power source system coil SC such that the phase difference ⁇ s therebetween becomes a predetermined target value ⁇ ms.
  • the power source side control circuit 14 has a current detection sensor SE 1 , a phase detection units 141 , 142 , a target value setting unit 143 , a power source side feedback control unit 144 , and a phase transmission unit 145 .
  • the current detection sensor SE 1 detects the current Is flowing in the power source resonance coil 13 .
  • a hall effect element, a magnetic resistance element or a detection coil or the like may be used as the current detection sensor SE 1 .
  • the current detection sensor SE 1 outputs a voltage signal according to, e.g., the waveform of the current I s .
  • the phase detection unit 141 detects the phase ⁇ vs of the voltage Vs applied to the power supply coil 12 , and outputs a voltage signal according to, e.g., the waveform of the voltage Vs.
  • the phase detection unit 141 may output the voltage Vs without any changes, or by dividing the voltage Vs by an appropriate resistor.
  • the phase detection unit 141 may be configured by a simple electric wire, or by one or more resistor elements.
  • the phase detection unit 142 detects the phase ⁇ is of a current Is flowing in the power source resonance coil 13 , based on an output from the current detection sensor SE 1 , and outputs a voltage signal according to, e.g., the waveform of the current Is.
  • the phase detection unit 142 may output the output of the current detection sensor SE 1 without any change.
  • the current detection sensor SE 1 may serve also as the phase detection unit 142 .
  • the target value setting unit 143 sets and stores the target value ⁇ ms of the phase difference ⁇ s. Therefore, a memory for storing the target value ⁇ ms is provided in the target value setting unit 143 . For example, “ ⁇ 180° ( ⁇ radians)” or “a value obtained by adding an appropriate correction value a to ⁇ 180°” is set as the target value ⁇ ms.
  • the target value ⁇ ms may be set by selecting from one or more data preliminarily stored, or may be set according to a command from a CPU, a keyboard, or the like.
  • the power source side feedback control unit 144 performs variable control of the resonance frequency fs of the power source resonance coil 13 such that the phase difference ⁇ s between the phase ⁇ vs of the voltage V s of the AC power supply 11 and the phase ⁇ is of the current Is of the power source resonance coil 13 is the set target value ⁇ ms.
  • the phase transmission unit 145 wirelessly transmits information concerning the phase ⁇ vs of the voltage Vs supplied to the power supply coil 12 to the power receiver side control circuit 24 as an analog signal or a digital signal.
  • the phase transmission unit 145 may transmit a signal obtained by, e.g., multiplying a voltage signal set according to the waveform of the voltage Vs by an integer in order to improve an S/N ratio.
  • the power receiver side control circuit 24 detects the phase ⁇ vs of the voltage VS supplied to the Power source system coil SC and the phase ⁇ ij of the current Ij flowing in the Power receiver system coil JC, and performs variable control of the resonance frequency fj of the Power receiver system coil JC such that the phase difference ⁇ j therebetween is a predetermined target value ⁇ mj.
  • the power source side control circuit 24 a current detection sensor SE 2 , a phase reception unit 241 , a phase detection unit 242 , a target value setting unit 243 , and a power receiver side feedback control unit 244 .
  • the current detection sensor SE 2 detects the current Ij flowing in the power receiver resonance coil 22 .
  • a Hall device, a magnetic resistance element, or a detection coil or the like may be used as the current detection sensor SE 2 .
  • the current detection sensor SE 2 outputs a voltage signal according to, e.g., the waveform of the current Ij.
  • the phase reception unit 241 receives and outputs information concerning the phase ⁇ vs transmitted from the phase transmission unit 145 . If the voltage signal is multiplied at the phase transmission unit 145 , frequency division is performed to demultiply the voltage signal at the phase reception unit 241 . The phase reception unit 241 outputs a voltage signal according to, e.g., the voltage Vs.
  • the phase detection unit 242 detects the phase ⁇ ij of the current Ij flowing in the power receiver resonance coil 22 , based on the output from the current detection sensor SE 2 .
  • the phase detection unit 242 outputs a voltage signal according to, e.g., the waveform of the current Ij.
  • the phase detection unit 242 may output the output of the current detection sensor SE 2 without any change.
  • the current detection sensor SE 2 may be configured to act also as the phase detection unit 242 .
  • the target value setting unit 243 sets and stores the target value ⁇ mj of the phase difference ⁇ j.
  • a memory for storing the target value ⁇ mj is provided in the target value setting unit 243 .
  • a value obtained by adding “ ⁇ 90° ( ⁇ /2 radians)” to the target value ⁇ ms in the power source side control circuit 14 is set as the target value ⁇ mj.
  • ⁇ 270° ( ⁇ 3 ⁇ /2 radians)” or “a value obtained by adding an appropriate value a to” 270°”, or the like is set as the target value ⁇ mj.
  • a method for setting the target value ⁇ mj, and the like are similar to those used when setting the target value ⁇ ms.
  • the power receiver side feedback control unit 244 performs variable control of the resonance frequency fj of the power receiver resonance coil 22 such that the phase difference ⁇ j between the phase ⁇ vs of the voltage Vs of the AC power supply 11 and the phase ⁇ ij of the current Ij of the power receiver resonance coil 22 is the target value ⁇ mj.
  • the respective of the target value setting unit 143 and the power source side feedback control unit 144 in the power source side control circuit 14 , and the target value setting unit 243 and the power receiver side feedback control unit 244 in the power receiver side control circuit 24 are simple examples of the resonance frequency control unit.
  • FIG. 3 is a block diagram depicting the wireless power transfer system depicted in FIG. 2 while focusing on a control system.
  • FIG. 3 illustrates in detail the power source side feedback control unit 144 of the power source 1 and the power receiver side feedback control unit 244 of the power receiver 2 .
  • phase detection units 141 , 142 , 241 , and 242 depicted in FIG. 2 are omitted.
  • the phase ⁇ is of the current Is flowing from the current detection sensor SE 1 to the power source resonance coil 13 is directly output.
  • the phase ⁇ is may be output via, e.g., the phase detection unit 142 provided in the power source side feedback control unit 144 .
  • the power source side feedback control unit 144 has a phase comparison unit 151 , an addition unit 152 , gain adjustment units 153 , 154 , a compensation unit 155 , a driver 156 , a polarity inversion unit 157 , and the like.
  • the phase comparison unit 151 compares the ⁇ is of the current Is detected by the current detection sensor SE 1 and the phase ⁇ vs of the voltage Vs of the AC power supply 11 , and outputs the phase difference ⁇ s therebetween.
  • the addition unit 152 subtracts (inverts and adds) the target value ⁇ ms set by the target value setting unit 143 from the phase difference ⁇ s output by the phase comparison unit 151 . Accordingly, when the phase difference ⁇ s and the target value ⁇ ms are matched, an output of the addition unit 152 is 0.
  • the output of the addition unit 152 is inverted in polarity by the polarity inversion unit 157 , and next input to the gain adjustment unit 154 , and then input to the compensation unit 155 .
  • the gain adjustment units 153 and 154 adjust a gain (amplification) corresponding to an input value or data, or convert data or the like such that control is correctly performed.
  • the compensation unit 155 determines a gain corresponding to, e.g., a low frequency component.
  • the power source side feedback control unit 144 may be regarded as a servo system performing feedback control on, e.g., an MEMS variable capacity device which is a capacitor 132 .
  • an appropriate servo filter for stabilization, speeding-up, and improvement in accuracy of the servo system may be used as the compensation unit 155 .
  • a filter circuit or a differentiation/integration circuit or the like for performing a PID (Proportional Integral Derivative Controller) operation in such a servo system is appropriately used.
  • the driver 156 outputs a control signal KSs to, e.g., an MEMS variable capacity device which is a capacitor 132 , and performs variable control of the capacitance of the MEMS variable capacity device.
  • the MEMS variable capacity device (MEMS variable capacitor) is configured to change electrostatic capacitance by providing, e.g., a lower electrode and an upper electrode on a glass substrate, and using change of a space due to flexure caused by an electrostatic attraction force which is generated by a voltage applied between the electrodes.
  • the MEMS variable capacity device (capacitor 132 ) may be configured such that an electrode for the capacitor, and an electrode for driving may be provided separately from each other.
  • the relationship between a voltage applied to the electrode for driving and an amount of the capacitance change is not linear.
  • a calculation for the conversion, or table conversion is performed appropriately in, e.g., the driver 156 .
  • the power receiver side feedback control unit 244 includes a phase comparison unit 251 , an addition unit 252 , gain adjustment units 253 , 254 , a compensation unit 255 , a driver 256 , and a polarity inversion unit 257 .
  • each unit of the power receiver side feedback control unit 244 is similar to that of each unit of the power source side feedback control unit 144 . Therefore, description of the operation of each unit of the power receiver side feedback control unit 244 is omitted.
  • the power source side control circuit 14 and the power receiver side control circuit 24 depicted in FIG. 2 , and the power source side feedback control unit 144 and the power receiver side feedback control unit 244 depicted in FIG. 3 , and the like may be implemented by software, or hardware, or a combination thereof.
  • control circuits and control units may be implemented using a computer including, e.g., a CPU, memories such as a ROM and a RAM, and other peripheral devices, and causing the CPU to execute appropriate computer programs. In that case, appropriate hardware circuits are combined with the computer.
  • FIG. 4A and FIG. 4B are diagrams for illustrating resonance frequency control in the wireless power transfer system depicted in FIG. 2 and FIG. 3 .
  • an axis of abscissa represents the frequency f [MHz] of the AC power supply 11
  • an axis of ordinates represents the magnitude [dB] of current I flowing in each coil.
  • an axis of abscissa represents the frequency f [MHz] of the AC power supply 11
  • an axis of ordinates represents the phase ⁇ [radian] of the current I flowing in each coil.
  • the phase ⁇ represents the phase difference 4 from the phase ⁇ vs of the voltage Vs of the AC power supply 11 , i.e., the phase difference ⁇ using the phase ⁇ vs of the voltage Vs supplied to the power supply coil 12 as a reference.
  • the phase ⁇ is 0 when the phase ⁇ corresponds to the phase ⁇ vs.
  • the last numbers 1 , 2 , 3 , 4 indicate correspondence relationship with the power supply coil 12 , the power source resonance coil 13 , the power receiver resonance coil 22 , the power extraction coil 23 , respectively.
  • FIG. 4A and FIG. 4B illustrate a case of performing resonance frequency control, in which the power source resonance coil 13 or a set of the power source resonance coil 13 and the power receiver resonance coil 22 is controlled such that the resonance frequencies fs, fj are 10 MHz.
  • the target value ⁇ ms is set to “ ⁇ radians ( ⁇ 180°)” in the target value setting unit 143
  • the target value ⁇ mj is set to “ ⁇ 3 ⁇ /2 radians ( ⁇ 270°)” in the target value setting unit 143 .
  • the target value ⁇ mj is set to a value “ ⁇ ms ⁇ /2” obtained by adding ⁇ /2 to the target value ⁇ ms, i.e., set to a phase being ⁇ /2 behind the target value ⁇ ms.
  • the current Is of the power source resonance coil 13 peaks at 10 MHz which corresponds to the frequency fd of the AC power supply 11 .
  • the phase ⁇ is of the current Is of the power source resonance coil 13 is ⁇ at 10 MHz which corresponds to the resonance frequency fs. In other words, the phase ⁇ is coincides with the target value ⁇ ms.
  • the power source resonance coil 13 may be regarded as a serial resonance circuit when viewed from the power supply coil 12 .
  • a reactance is capacitive and becomes closer to ⁇ /2, and at the higher frequency fd, the reactance is inductive and becomes closer to ⁇ 3 ⁇ /2.
  • the phase ⁇ is of the current Is flowing through the power source resonance coil 13 largely changes in the vicinity of the resonance frequency fs.
  • the resonance frequency fs of the power source resonance coil 13 may be made to coincide with the frequency fd of the voltage Vs highly accurately by being controlled such that the phase ⁇ is, i.e., the phase difference ⁇ s is ⁇ .
  • the current I flowing in the power supply coil 12 also peaks at the resonance frequency fs.
  • the phase ⁇ i of the current I flowing in the power supply coil 12 is 0 or a leading phase in the vicinity of the resonance frequency fs.
  • the phase ⁇ i becomes ⁇ /2.
  • the current Ij of the power receiver resonance coil 22 peaks at 10 MHz which coincides with the frequency fd of the AC power supply 11 .
  • the phase ⁇ ij of the current Ij of the power receiver resonance coil 22 is ⁇ 3 ⁇ /2 at 10 MHz which coincides with the resonance frequency fs. In other words, the phase ⁇ ij coincides with the target value ⁇ mj.
  • the phase difference ⁇ decreases and is close to ⁇ /2.
  • the phase difference ⁇ increases and is close to ⁇ 5 ⁇ /2, i.e., ⁇ /2.
  • the phases ⁇ is and ⁇ ij of the currents Is and Ij respectively flowing in the power source resonance coil 13 and the power receiver resonance coil 22 largely change in the vicinity of the resonance frequencies fs and fj, respectively.
  • the phases ⁇ is and ⁇ ij i.e., the phase differences ⁇ s, ⁇ j are ⁇ or ⁇ 3 ⁇ /2
  • the resonance frequencies fs and fj of the power source resonance coil 13 and the power receiver resonance coil 22 may be made to highly accurately coincide with the frequency fd of the voltage Vs.
  • the resonance frequencies of the Power source system coil SC and the Power receiver system coil JC may be made to accurately coincide with the frequency fd of the AC power supply 11 .
  • Power may constantly be transferred from the power source device 3 to the power receiver device 4 at maximum efficiency.
  • control is performed, based on the phase difference A of the coil current with respect to the voltage Vs of the ⁇ power supply.
  • accurate control may be performed without influence of variation in the amplitude of the current, which affects control, e.g., when using a sweep search method.
  • the sweep search method e.g., sweeping is performed on L or C in the Power source system coil SC or the Power receiver system coil JC.
  • a position at which the current value of the coil is maximized (peaked) is searched for in a trial-and-error manner.
  • FIG. 5A and FIG. 5B are diagrams for illustrating conditions for simulation in the wireless power transfer system depicted in FIG. 2 and FIG. 3 .
  • the conditions for simulation are that the power supply coil 12 and the power source resonance coil 13 are coaxially arranged on a same plane, and that the power receiver resonance coil 22 and the power extraction coil 23 are also arranged coaxially on a same plane.
  • the distance dd between the Power source system coil SC (the power supply coil 12 and the power source resonance coil 13 ) and the Power receiver system coil JC (the power receiver resonance coil 22 and the power extraction coil 23 ) is set at 25 mm.
  • the drive frequency (the frequency fd of the AC power supply 11 ) is set at 7 MHz.
  • the load (the resistance value of the load device 21 ) is set at 10 ⁇ .
  • the thickness of each coil is set at ⁇ 0.5 mm.
  • the outside diameter of the power supply coil 12 is set at ⁇ 30 mm.
  • the number of turns of the power supply coil 12 is set at 1.
  • the outside diameter of the power source resonance coil 13 is set at ⁇ 40 mm.
  • the number of turns of the power source resonance coil 13 is set at 5.
  • the outside diameter of the power receiver resonance coil 22 is set at ⁇ 30 mm.
  • the number of turns of the power receiver resonance coil 22 is set at 5.
  • the outside diameter of the power extraction coil 23 is set at ⁇ 20 mm.
  • the number of turns of the power extraction coil 23 is set at 1.
  • the distance (pitch) between the centers of adjacent windings of each of the power source resonance coil 13 and the power receiver resonance coil 22 is set at 0.8 mm.
  • FIG. 6A and FIG. 6B are diagrams depicting a result of simulation in the wireless power transfer system depicted in FIG. 2 and FIG. 3 , which is performed under the conditions for simulation illustrated in FIG. 5A and FIG. 5B .
  • the axis of ordinates represents the amplitude of a drive voltage, which is normalized (the maximum amplitude is set to “1”).
  • the axis of abscissas represents time normalized ( 1/7 MHz is set to “1”).
  • the reference sign ⁇ d represents phase delays of a power source side drive voltage LL 1 and a power receiver side drive voltage LL 2 .
  • the axis of ordinates represent a power transfer efficiency (the maximum efficiency is set to “1”), and the axis of abscissas represents a phase delay ⁇ d (deg: °).
  • a power transfer efficiency decreases with increase of the phase delays ⁇ d of the power source side drive voltage LL 1 and the power receiver side drive voltage LL 2 . Particularly, it is seen that when the phase delay ⁇ d exceeds 40°, the power transfer efficiency decreases largely.
  • a delay time td corresponding to a phase delay of 1° is calculated as follows.
  • the delay time Td corresponding to a phase delay of, e.g., 30° is calculated as follows.
  • the power transfer efficiency decreases even for a very short delay time td.
  • the power source 1 and the power receiver 2 each have a communication circuit which transmits and receives information concerning the positions of the transmitter and the receiver, electric power to be transferred, and the like. It is difficult for these communication circuits to process data for phase control of a drive voltage of 7 MHz (generally, hundreds of KHz to tens of MHz).
  • the power source 1 is equipped with a dedicated phase transmission unit 145 .
  • the power receiver 2 is equipped with a dedicated phase reception unit 241 .
  • the phase of a voltage waveform of the AC power supply 11 which is obtained in the power source 1 , is accurately transferred to the power receiver 2 without delay.
  • the dedicated phase transmission unit 145 and the dedicated phase reception unit 241 are provided in the power source 1 and the power receiver 2 , respectively. Accordingly, hardware volume increases. Thus, cost increases.
  • FIG. 7 is a block diagram depicting a wireless power transfer system according to a first embodiment.
  • a power source side control unit 16 and a power source side communication unit 17 are provided in a power source 1 , instead of the dedicated phase transmission unit 145 .
  • the wireless power transfer system is configured so that a power receiver side control unit 26 , a power receiver side communication unit 27 , and a power receiver side phase adjustment oscillation unit 28 are provided in the power receiver 2 , instead of the dedicated phase reception unit 241 .
  • the wireless power transfer system according to the first embodiment does not need high-speed data transfer as needed in the wireless power transfer system, e.g., depicted in FIG. 3 . Therefore, the power source side communication unit 17 and the power receiver side communication unit 27 may act also as a communication circuit for transmitting and receiving information concerning the positions of the transmitter and the receiver, electric power to be transferred, and the like.
  • the wireless power transfer system according to the first embodiment need not perform real-time phase control of a resonance frequency of, e.g., hundreds of KHz to tens of MHz.
  • a communication circuit generally provided therein may be used without change.
  • each of an AC power supply 11 , a power supply coil 12 , a power source resonance coil 13 , a capacitor 132 , a current detection sensor SE 1 , and a power source side feedback control unit 144 , and the like of the power source 1 are substantially similar to those described with reference to FIG. 3 .
  • each of a power receiver resonance coil 22 , a power extraction coil 23 , a capacitor 222 , a current detection sensor SE 2 , and a power receiver side feedback control unit 244 , and the like of the power receiver 2 are substantially similar to those described with reference to FIG. 3 .
  • a target value ⁇ ms in the power source 1 is output from a target value setting unit 143 .
  • a target value ⁇ mj in the power receiver 2 is output from a target value setting unit 243 .
  • FIG. 8 is a block diagram depicting a wireless power transfer system according to a second embodiment.
  • FIG. 9 to FIG. 12 are diagrams for illustrating an operation in the wireless power transfer system depicted in FIG. 8 .
  • FIG. 8 to FIG. 10 illustrate the system while focusing on the power source side control unit 16 , the power source side communication unit 17 , the AC power supply 11 , the power supply coil 12 , the power source resonance coil 13 , the capacitor (variable capacity device) 132 , and the power source side feedback control unit 144 in the power source 1 .
  • phase comparison unit (second phase comparison unit) 151 of the power source 1 is provided in the power source side feedback control unit 144 .
  • the phase comparison unit 151 and the power source side feedback control unit 144 are drawn separately from each other.
  • FIG. 8 to FIG. 10 illustrate the system while focusing on a power receiver side control unit 26 , a power receiver side communication unit 27 , a power receiver side phase adjustment oscillation unit 28 , the power receiver resonance coil 22 , a power take-out unit 23 , a capacitor 222 , and a power receiver side feedback control unit 244 in the power receiver 2 .
  • phase comparison unit 251 of the power receiver 2 is provided in the power receiver side feedback control unit 244 .
  • the phase comparison unit 251 and the power receiver side feedback control unit 244 are drawn separately from each other.
  • a rectification circuit 211 and a load device 21 having a load (e.g., a battery: a resistance value RL) 212 , and a dummy load 29 having a resistance value RL′ which is substantially equal to the resistance value RL of the load 212 , are drawn together with switches SW 1 to SW 4 .
  • each of the power supply coil 12 , the power source resonance coil 13 , the power receiver resonance coil 22 , and the power extraction coil 23 is drawn by depicting an equivalent circuit, using resistors R 1 , R 2 , R 13 , and R 4 , and inductors L 1 , L 2 , L 3 , and L 4 .
  • Currents flowing in the power supply coil 12 , the power source resonance coil 13 , the power receiver resonance coil 22 , and the power extraction coil 23 are designated as I 1 , I 2 , I 3 , and I 4 .
  • a target value ⁇ ms in the power source 1 is output from the power source side control unit 16
  • a target value ⁇ mj in the power receiver 2 is output from the power receiver side control unit 26 .
  • the wireless power transfer system according to the second embodiment is configured to be substantially similar to the wireless power transfer system according to the first embodiment, except that the power source 1 does not have a target value setting unit 143 , and that the power receiver 2 does not have a target value setting unit 243 .
  • an operation of the wireless power transfer system according to the first embodiment differs only in places from which the target values ⁇ ms and ⁇ mj are output, and is similar to an operation of the wireless power transfer system according to the second embodiment which will be described below.
  • each target value may be controlled as an optimal value for the wireless power transfer system to be used.
  • each target value may be controlled by being changed to implement another function.
  • the target value (target value of the phase difference ⁇ s) ⁇ ms for the power source side feedback control unit 144 is output from the power source side control unit 16 .
  • the AC power supply 11 is controlled by a control signal Sps output from the power source side control unit 16 .
  • the target value (target value of the phase difference ⁇ j) ⁇ mj for the power receiver side feedback control unit 244 is output from the power receiver side control unit 26 .
  • the power receiver side phase adjustment oscillation unit 28 is controlled by a control signal Spj output from the power receiver side control unit 26 .
  • the power receiver side phase adjustment oscillation unit 28 in the power receiver 2 outputs a signal (voltage VB) having a frequency to be used for power transfer, i.e., a fixed oscillating frequency being equal to that of the AC power supply 11 in the power source 1 .
  • the AC power supply 11 and the power receiver side phase adjustment oscillation unit 28 are controlled using, e.g., a crystal oscillator such that the oscillating frequencies thereof are accurately equal to each other.
  • a switch SW 1 is provided in the power receiver side resonance coil 22 .
  • a switch SW 2 is provided between the power receiver side phase adjustment oscillation unit 28 and the power receiver resonance coil 22 .
  • a switch SW 3 is provided between the power extraction coil 23 and the load device 21 .
  • a dummy load 29 is provided via a switch SW 4 between both ends of the power extraction coil 23 .
  • the switches SW 1 to SW 4 are, e.g., n-channel type MOS transistors (nMOS transistors) each having a gate to which a control signal is applied.
  • nMOS transistors n-channel type MOS transistors
  • a control signal CSj output from the power receiver side control unit 26 is applied to the control terminal (gate of each nMOS transistor) of each of the switches SW 1 and SW 3 .
  • a control signal /CSj obtained by inverting the control signal CSj at an inverter is applied to the control terminal of each of the switches SW 2 and SW 4 .
  • the power receiver side phase adjustment oscillation unit 28 of the power receiver 2 is put into an operating state (i.e., turned on) by the control signal Spj output from the power receiver side control unit 26 .
  • the resistance value RL′ of the dummy load 29 is set to be substantially equal to the resistance value RL of the load 212 of the load device 21 .
  • the target value ⁇ mj given to the power receiver side feedback control unit 244 from the power receiver side control unit 26 is set to, e.g., 0°.
  • the output voltage VB from the power receiver side phase adjustment oscillation unit 28 is used to adjust the resonance frequency in the power receiver 2 , and therefore, the power capacity of the voltage VB is minute.
  • a rectification circuit (rectification IC) 211 of the load device 21 may not be operated by the voltage VB, and the resistance value RL of the load resistor 212 may not be accurately reflected due to non-linear characteristics.
  • the dummy load 29 being comparable to the load resistor 212 is connected to the power extraction coil 23 , instead of the actual load device 21 .
  • the adjustment of the resonance frequency of the power receiver 2 is made by the voltage VB corresponding to the minute power capacity.
  • the power receiver side feedback control unit 244 controls the electrostatic capacity of the capacitor 222 via a control signal KSj to be a predetermined value such that the phase difference ⁇ j is equal to the target value ⁇ mj.
  • the resonance frequency of the power source 1 is adjusted in a time Tcs.
  • the resonance frequency of the power receiver 2 is adjusted in a time Tcj.
  • the above adjustment of the resonance frequency in the power receiver 2 is performed in the latter half Tcj of the time in which resonance adjustment processing is performed.
  • the adjustment of the resonance frequency in the power source 1 is performed.
  • the AC power supply 11 of the power source 1 is put into a low output state (adjustment output state) by a control signal Sps output from the power source side control unit 16 .
  • the AC power supply 11 In the low output state of the AC power supply 11 , the AC power supply 11 does not output a voltage for transferring power to the power receiver 2 .
  • the AC power supply 11 simply outputs a low voltage for adjusting the resonance frequency in the power source 1 .
  • the feedback control is such that, as described with reference to FIG. 2 to FIG. 4B , e.g., the power source side feedback control unit 144 controls the electrostatic capacity of the capacitor 132 via a control signal KSs to a predetermined value so that the phase difference ⁇ s is equal to the target value ⁇ ms.
  • the adjustment of the resonance frequency in the power source 1 is not necessarily performed immediately before the adjustment of the resonance frequency in the power receiver 2 .
  • the adjustment of the resonance frequency in the power source 1 may be performed simultaneously with or immediately after the adjustment of the resonance frequency in the power receiver 2 , or alternatively, at another appropriate timing.
  • the power receiver side phase adjustment oscillation unit 28 of the power receiver 2 is put into a stopped state (off-state) by the control signal Spj output from the power receiver side control unit 26 .
  • the switch SW 2 is turned off, the power receiver side phase adjustment oscillation unit 28 is disconnected from the power receiver resonance coil 22 .
  • the power receiver resonance coil 22 receives power from the power source resonance coil 13 in the power source 1 by magnetic field resonance (magnetic field resonating). At that time, the power extraction coil 23 is connected to the load device 21 by the turn-on of the switch SW 3 and the turn-off of the switch SW 4 .
  • the AC power supply 11 is put into an operating state (which is not a low power operating state, and is a normal operating state) by a control signal Sps output from the power source side control unit 16 .
  • the resonance frequency of the power source resonance coil 13 in the power source 1 is controlled so as to coincide with the frequency of the AC power supply 11 in the time Tcs.
  • the resonance frequency of the power receiver resonance coil 22 in the power receiver 2 is controlled so as to coincide with the frequency of the power receiver side phase adjustment oscillation unit 28 .
  • the frequency of the AC power supply 11 and the frequency of the power receiver side phase adjustment oscillation unit 28 are accurately controlled using, e.g., a crystal oscillator.
  • the power transfer by the magnetic field resonance from the power source 1 to the power receiver 2 may be performed with high power transfer efficiency.
  • the resonance frequency adjustment times (Tcs, Tcj: resonance adjustment) in the power source 1 and the power receiver 2 are repeated at predetermined intervals.
  • the intervals for repeating the resonance adjustment may variously be set according to the number of the power source 1 and the power receiver 2 , the power capacity thereof, or the surrounding environment thereof, or the like. For example, a several-minute interval may be set as the interval for repeating the resonance adjustment.
  • steps ST 101 and ST 201 e.g., it is checked whether the power receiver 2 is present within a range in which power may be transferred by the power source 1 to the power receiver 2 .
  • the transfer of information concerning the position and the inclination of the power receiver 2 , and electric power to be transmitted, and the authentication of the power receiver 2 in a paid power transfer system are performed.
  • step ST 102 the processing proceeds to step ST 102 , whereupon the adjustment (resonance adjustment) of the resonance frequency in the power source 1 is started, which has been described with reference to the time Tcs depicted in FIG. 9 and FIG. 11 .
  • step ST 103 the output voltage VA of the AC power supply 11 is set to the adjustment output voltage (low output voltage).
  • step ST 104 the phase difference is controlled.
  • step ST 104 phase difference control processing is performed by the power source side feedback control unit 144 .
  • step ST 105 the phase difference control processing in step ST 104 is repeated until the phase difference ⁇ s becomes less than the target value ⁇ ms.
  • step ST 105 if it is determined in step ST 105 that the phase difference ⁇ s is within a range prescribed by the target value ⁇ ms, the processing proceeds to step ST 106 in which the resonance adjustment processing by the power source 1 is terminated. Then, the processing proceeds to step ST 107 .
  • step ST 202 when the resonance frequency adjustment processing by the power source 1 is terminated in the time Tcs, in step ST 202 , on the power receiver side, the adjustment of the resonance frequency (resonance adjustment) in the power receiver 2 is started in a time Tcj subsequent to the time Tcs.
  • the power receiver 2 recognizes the termination of the resonance frequency adjustment processing in the power source 1 by the communication between the power source side communication unit 17 and the power receiver side communication unit 27 .
  • the resonance adjustment is started by the power receiver 2 .
  • step ST 203 the switching of the switches SW 1 to SW 4 described with reference to FIG. 9 is performed. Then, the processing proceeds to step ST 204 in which the power receiver side phase adjustment oscillation unit 28 is put into an operating state (in which the voltage VB is output) by the power receiver side control unit 26 .
  • the switches SW 1 and SW 3 are turned off.
  • the switches SW 2 and SW 4 are turned on.
  • the output voltage VB of the power receiver side phase adjustment oscillation unit 28 is applied to both ends of the power receiver resonance coil 22 .
  • the load device 21 is disconnected from the power extraction coil 23 , and instead, the dummy load 29 is connected to the power extraction coil 23 .
  • step ST 205 the processing proceeds to step ST 205 in which phase difference control processing is performed by the power receiver side feedback control unit 244 .
  • step ST 206 the phase difference control processing in step ST 205 is repeated until the phase difference ⁇ j becomes less than the target value ⁇ mj.
  • step ST 206 if it is determined in step ST 206 that the phase difference ⁇ j is within a range prescribed by the target value ⁇ mj, the processing proceeds to step ST 207 in which the switching of the switches SW 1 to SW 4 described with reference to FIG. 10 is performed. Then, the processing proceeds to step ST 208 .
  • step ST 208 the power receiver side phase adjustment oscillation unit 28 is put into a stopped state (the output voltage VB is stopped) by the power receiver side control unit 26 . Then, the processing proceeds to step ST 209 in which the resonance adjustment processing in the power receiver 2 is terminated. The power receiver side control unit 26 notifies the power source side of the termination of the resonance adjustment processing.
  • the power source 1 recognizes the termination of the resonance frequency adjustment processing in the power receiver 2 by the communication between the power source side communication unit 17 and the power receiver side communication unit 27 .
  • step ST 107 power transmission is started by the power source 1 .
  • step ST 108 the AC power supply 11 is put into a normal operating state by the control signal Sps output from the power source side control unit 16 , instead of being put into a low power operating state.
  • the AC power supply 11 outputs a power transmission output voltage VB.
  • both of the power source 1 and the power receiver 2 are put into a state in which the resonance frequency adjustment is completed. In this state, power transfer by magnetic field resonance from the power source 1 to the power receiver 2 is performed. Thus, power transfer with high power transfer efficiency is made possible.
  • step ST 109 the processing proceeds to step ST 109 . If it is determined in step ST 109 that a prescribed time has passed, the processing returns to step ST 101 (ST 201 ). Then, similar processing is repeated. In other words, the adjustment of the resonance frequency in the power source 1 and the power receiver 2 is repeated at predetermined intervals.
  • step ST 103 the output voltage VA of the AC power supply 11 is set to a low output voltage for adjustment.
  • both of the adjustment of the resonance frequency in the power source 1 and the adjustment of the resonance frequency in the power receiver 2 may be performed in parallel.
  • the adjustment of the resonance frequency in the power source 1 is not necessarily performed immediately before the adjustment of the resonance frequency in the power receiver 2 .
  • the adjustment of the resonance frequency in the power source 1 may be performed simultaneously with or immediately after the adjustment of the resonance frequency in the power receiver 2 , or alternatively, at another appropriate timing.
  • the power source it is not necessary for the power source to transmit the phase of the voltage waveform of the AC power supply accurately without delay to the power receiver.
  • a dedicated communication circuit capable of performing high-speed data transfer is unnecessary.
  • the hardware volume may be reduced.
  • the cost may be decreased.
  • FIG. 13 is a block diagram depicting a wireless power transfer system according to the third embodiment.
  • FIG. 14 and FIG. 15 are diagrams for illustrating an operation of the wireless power transfer system depicted in FIG. 13 .
  • a power source 1 includes a temperature sensor (second temperature sensor) 100 .
  • the power receiver 2 includes a temperature sensor (first temperature sensor) 200 .
  • the temperature sensor 100 measures (detects) the temperature of each of a power supply coil 12 and a power source resonance coil 13 in the power source 1 , and outputs a temperature signal (second temperature signal) Tss to a power source side control unit 16 .
  • the temperature sensor 200 measures the temperature of each of a power receiver resonance coil 22 and a power extraction coil 23 in the power receiver 2 , and outputs a temperature signal (first temperature signal) Tsj to a power receiver side control unit 26 .
  • the temperature sensor 100 has only to measure the temperature of the power source resonance coil 13 .
  • the temperature sensor 200 has only to measure the temperature of the power receiver resonance coil 22 .
  • a power supply time (time Tps) and a resonance adjustment time (times Tcs and Tcj) are substantially the same as those depicted in FIG. 11 .
  • time Tps time
  • Tcs and Tcj resonance adjustment time
  • steps ST 101 to ST 108 on the power source side power source 1
  • steps ST 201 to ST 209 on the power receiver side power receiver 2
  • steps ST 101 to ST 108 on the power source side power source 1
  • steps ST 201 to ST 209 on the power receiver side power receiver 2
  • step ST 209 on the power receiver side resonance adjustment processing in the power receiver 2 is terminated.
  • the power source side is notified of the termination of the resonance adjustment processing.
  • step ST 210 on the power receiver side the processing proceeds to step ST 210 on the power receiver side.
  • step ST 210 on the power receiver side it is determined whether the temperature sensor 200 provided in the power receiver 2 detects an abnormality, i.e., whether temperature signals Tsj by the temperature sensor 200 representing the temperature of the power receiver resonance coil 22 and the temperature of the power extraction coil 23 indicate abnormal values. If it is determined in step ST 210 that the temperature sensor 200 does not detect an abnormality, power transfer from the power source 1 to the power receiver 2 is continued in an unchanged state.
  • step ST 210 if it is determined in step ST 210 that the temperature sensor 200 detects an abnormality, i.e., the temperature signal Tsj exceeds a threshold temperature Tha indicating an abnormality, the processing proceeds to step ST 211 in which the detection of an abnormality by the temperature sensor 200 is transmitted to the power receiver side.
  • the detection of an abnormality in step ST 211 on the power receiver side is transmitted to the power receiver side.
  • step ST 110 the detection of the abnormality is processed as the power transmitting/receiving temperature monitoring.
  • step ST 212 it is determined whether the power receiver side temperature sensor 200 detects a normal value. If it is determined in step ST 212 that the power receiver side temperature sensor 200 does not detect a normal value, the power receiver 2 maintains the state without change and waits for the detection of a normal value by the power receiver side temperature sensor 200 .
  • a power transmission output voltage VA is stopped by performing processing in step ST 112 on the power source side, as will be described below.
  • the power transfer is stopped.
  • the level of the temperature signal Tsj output from the power receiver side temperature sensor 200 is lowered with time.
  • step ST 212 If it is determined in step ST 212 on the power receiver side that the power receiver side temperature sensor 200 detects a normal value, the processing proceeds to step ST 213 in which the power source side is notified of the detection of a normal value by the power receiver side temperature sensor 200 . Then, the processing returns to step ST 210 in which similar processing is performed.
  • step ST 108 on the power source side the AC power supply 11 outputs a power transmission output voltage VB for performing a usual power transmission operation. Then, the processing proceeds to step ST 110 in which power transmitting/receiving temperature monitoring is performed.
  • the power transmitting/receiving temperature monitoring in step ST 110 includes the monitoring of the temperature of each of the power supply coil 12 and the power source resonance coil 13 by the temperature sensor 100 of the power source 1 , and the monitoring of the temperature of each of the power receiver resonance coil 22 and the power extraction coil 23 by the temperature sensor 200 of the power receiver 2 .
  • the temperature signal Tss detected by the power source side temperature sensor 100 is input to the power source side control unit 16 without change.
  • the temperature signal Tsj detected by the power receiver side temperature sensor 200 is transmitted to the power source side control unit 16 via communication (communication units 17 , 27 , and the like).
  • step ST 111 it is determined whether the power source side temperature sensor 100 or the power receiver side temperature sensor 200 detects an abnormality. If it is determined that both of the sensors do not detect an abnormality, the power transfer from the power source 1 to the power receiver 2 is continued while performing the power transmitting/receiving temperature monitoring.
  • step ST 111 if it is determined in step ST 111 that at least one of the power source side temperature sensor 100 or the power receiver side temperature sensor 200 detects an abnormality, the processing proceeds to step ST 112 in which the output voltage VA for power transmission is stopped.
  • the power source side control unit 16 stops an operation of the AC power supply 11 by a control signal Sps.
  • step ST 112 If the output voltage VB for power transmission is stopped in step ST 112 , then, the processing proceeds to step ST 113 in which the power transmitting/receiving temperature monitoring is performed again.
  • step ST 114 it is determined whether both of the power source side temperature sensor 100 and the power receiver side temperature sensor 200 detect a normal value. If it is determined that at least one of the power source side temperature sensor 100 and the power receiver side temperature sensor 200 detects an abnormality, the power source 1 continues to stop the output voltage VB for power transmission, while performing power transmitting/receiving temperature monitoring.
  • step ST 114 it is determined in step ST 114 that both of the power source side temperature sensor 100 and the power receiver side temperature sensor 200 detect normal values, the processing returns to step ST 101 (ST 201 ).
  • target value setting units 143 and 243 may be provided in the power source 1 and the power receiver 2 , respectively, to output target values ⁇ ms and ⁇ mj.
  • the number of the power sources 1 and that of the power receivers 2 are 1. It is apparent that the number of the power sources 1 and that of the power receivers 2 each may be plural.
  • the power transfer from the power source resonance coil (LC resonator) 13 to the power receiver resonance coil (LC resonator) 22 is not limited to that using a magnetic field resonance (magnetic field resonating).
  • the power transfer may use, e.g., an electric field resonance (electric field resonating).

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WO2014118895A1 (ja) 2014-08-07
JPWO2014118895A1 (ja) 2017-01-26
CN104956566B (zh) 2018-11-13
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KR101746318B1 (ko) 2017-06-12
EP2953235B1 (en) 2018-09-12

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